Semi-conductor test systems are used for testing integrated circuit devices to verify their performance characteristics. For limited volume testing, the integrated circuit device can be placed in a test fixture that is mounted on a device-under-test (DUT) board, or the DUT board can be docked with a semi-conductor wafer prober or package handler for high volume production testing.
A problem arises when the xe2x80x9ctest headxe2x80x9d assembly, currently used on industry testers, docks (comes in contact) with the DUT board assembly. The movable test head docks with a prober. The prober holds the DUT board assembly and moves product wafers to the probe tips and removes wafers after test. When the test head assemblies dock with a prober, the hardware which holds the DUT board assembly gets deflected. This deflection causes non-symmetrical distortion of the probe tip plane. The probe mechanism must be adjusted in order to maintain a constant plane between the probe tip plane and the DUT board assembly. Because of the time consuming process of adjusting the probe tip plane and the probe mechanism and the difficulty in observing and manipulating the probe mechanism, current systems are inefficient and difficult to use. The non-symmetrical distortion of the probe tip plane and the probe mechanism creates time consuming adjustments.
A probe planarity compensating and aligning mechanism can be used to prepare the DUT before the test process to eliminate the time consuming adjustment process. A ceramic substrate used in the DUT is best positioned for testing if it can be rigidly mounted. Hardened brackets called hard stops are attached to the ceramic substrate to improve the mounting capability of the ceramic substrate. In order to attach these hard stops a toughened, thermally cured, modified structural epoxy is used to attach the hard stops to the ceramic substrate. The hard stops are required to be attached consistently, efficiently and with precision. The epoxy thickness dimensions, corrosive processing and elevated temperatures create difficulties in the attachment process. The thermal coefficient of expansion of the materials cause the components to shift when thermal energy is added to the components during the attachment process. What is needed in the art is a device that can enable the attachment process to be accomplished while maintaining consistent attachment precision of the hard stop to the substrate.
An exemplary embodiment is a fixture for securing hard stops to a substrate. The fixture has a base which provides support to the fixture. The base has a cavity configured for nestably supporting a substrate. A top plate is mounted on the base, the top plate is configured for mounting the substrate. An alignment plate is disposed on the top plate separate from the base. An adjusting plunger assembly is coupled to the base. The adjusting plunger assembly is configured for use with attaching a hard stop to the substrate. A plunger is coupled to the base substantially perpendicular to the adjusting plunger assembly. The plunger is configured for use with supporting the substrate. A method of using a fixture is disclosed comprising disposing a substrate in a base of the fixture and mounting a hard stop to the substrate. An adhesive is disposed between the hard stop and the substrate. The substrate is mounted between a plunger and a top plate. The hard stop on the substrate is aligned with an alignment plate. An adjusting plunger assembly is adjusted to mount the hard stop to the substrate.